Fix for #5695 - Migration steps' status displayed before the migration completed

The migration steps' status was already being shown as succeeded instead of showing an "unchecked" list of
steps.
These changes will make the steps being "checked" one by one as the migration advances.

app/src/main/java/org/mozilla/fenix/migration/MigrationProgressActivity.kt

@@ -102,7 +102,13 @@ internal fun MigrationResults.toItemList() = filterKeys {
         type,
         status.success
     )
-}
+}.toMutableList()
+    .plus(
+        whiteList
+            .filterKeys { !this.containsKey(it) }
+            .keys
+            .map { MigrationItem(it, false) }
+    ).sortedBy { it.migration.javaClass.simpleName }
 
 internal data class MigrationItem(val migration: Migration, val status: Boolean)